Ordinary cells "reprogrammed" to act like embryonic stem cells
contain characteristic errors that indicate they have been
incompletely transformed, according to
a
study
led by a Salk Institute researcher.

The so-called induced pluripotent stem cells contain
characteristic errors at certain points in the cells' genome, the
entire set of genetic information in an organism, said lead author
Joseph R.
Ecker
, director of Salk's
Genomics Analysis Laboratory
.

The study is the first to completely examine the differences in
the IPS cells genome, and provides a roadmap to studying these
errors and perhaps correcting them so these cells can be used for
human therapy, Ecker said.

Previous studies had seen indications of errors, but they were
like looking through a keyhole, Ecker said.This study, using
equipment from San Diego's
Illumina Inc
., examined each letter
of the genetic alphabet in these cells, and the material associated
with these cells that control their activity, Ecker said. This
"epigenetic" material bound up with genes can cause differences in
how two cells operate, even though their genes are the same.

Discovery of IPS cell technology in 2006 in animals, and in 2007
for humans, promises to transform the contentious field of human
embryonic stem cell research. Many object to using these cells,
derived from days-old embryos, on ethical or religious grounds. The
embryos, which they say are human lives, are killed to get the
cells. But the reprogrammed cells, such as skin cells, don't raise
those objections with groups such as the Roman Catholic Church.